1. Field of Invention
The present invention relates to a control device and method. More particularly, the present invention relates to a memory control device and method.
2. Description of Related Art
Conventionally, graphic memory and main memory of a system are separately controlled. In general, a graphic engine manages the graphic memory while a north bridge controls the error check correction of the main memory. Hence, graphic memory and main memory are unrelated to each other. However, due to rapid progress in technologies, memory speed has increased correspondingly. In one type of design known as unified memory architecture (UMA), the graphic engine merges with the North Bridge while the graphic memory merges with the main memory. Instruction data to be accessed by an address is normally stored inside the main memory. Most main memory includes error check correct (ECC) function. Sometimes, the error-check-correct (ECC) function can be disabled.
However, some data attributes do not require error checking. For example, if data are sent to the graphic engine for display purpose only, error checking may be skipped. Even if errors occur in some of the data, the system remains stable. Furthermore, additional error-check-correction bits in the hardware are not required. Nevertheless, some data accessed by an instruction address must be error checked. For example, if the data pointed to by the instruction address are used for administrating the system, such data must be stored in a memory with error check correction capability so that accurate results are produced. In an integrated memory system, error-check-correction operation is executed even if the degree of data accuracy demanded is low. Hence, processing time is wasted in accurate checking and correcting of error permissible data such as graphic memory data.